1. Field of the Invention
The present invention relates to a video signal recording/reproducing apparatus equipped with a rotary head drum for recording or reproducing a video signal to or from a magnetic tape, and more particularly to a head drum and tape driving device of a video tape recorder (VTR) which can transport a magnetic tape by means of a single motor which is also used for driving the head drum.
2. Description of the Related Art
A conventional videocassette recorder (VCR) requires a motor for driving the head drum and another motor for driving a capstan and a reel.
FIGS. 1A and 1B illustrate a power transmission system of the conventional VCR equipped with motors thus described. FIG. 1A is a plan view and FIG. 1B is a left side view with certain elements removed for clarity.
In FIGS. 1A and 1B, a drum motor 82 drives a head drum 80 and a capstan motor 92 drives a capstan 90 for transporting a magnetic tape 85. Power is transmitted from the capstan motor 92 to a supply reel gear 83 or take-up reel gear 84 through a pulley 93, a belt 95, a reel driving pulley 94, a reel driving gear 97, gears 96 and 98 and an idler gear 91.
Idler gear 91 is carried by a bracket 99 which is pivoted on the common axis of gears 96 and 98, whereby idler gear 91 is coupled with gear 98.
Accordingly, when a tape is inserted into a tape cassette deck to thereby perform a reproduction operation (play mode), the tape 85 is pressed against a periphery of the head drum 80 by means of guide posts 78a and 78b to thereby contact the capstan 90 in a known manner. A pinch roller 86 is moved to thereafter press the tape 85 against the capstan 90 in a known manner.
If the capstan motor 92 is driven under a state where the tape 85 closely contacting the capstan 90, as pressed by the pinch roller 86, the capstan 90 rotates counter-clockwise and the pinch roller 86 is rotated clockwise by frictional force to thereby move the tape therebetween. At the same time, pulley 93 installed under the capstan motor 92 also rotates counter-clockwise causing the reel driving pulley 94, coupled to pulley 93 by the belt 95, to rotate counter-clockwise.
The reel driving gear 97 secured on the same shaft with the reel driving pulley 94 also rotates counter-clockwise, and the gears 96 and 98 thus rotate clockwise. When the gears 96 and 98 rotate clockwise, the bracket 99 and the idler gear 91 which are pivotably supported on the axis of the gears 96 and 98 are moved toward a take-up reel 89, and the idler gear 91 is rotated counter-clockwise and placed in engagement with the take-up reel gear 84. If the idler gear 91 rotates counter-clockwise the take-up reel gear 84 rotates clockwise and the take-up reel 89 also rotates clockwise. Accordingly, the tape 85 is transferred from a supply reel 88 and is wound on the take-up reel 89. At the same time, the drum motor 82 rotates to thereby drive the head drum 80 and a head disposed around the head drum reads a signal of the tape 85.
During rewinding of the tape, the capstan motor 92 rotates in an opposite direction from the reproduction operation (clockwise) to thereby transport the tape 85 toward to supply reel 88. During this operation, the reel driving gear 97 secured on the same axis with the reel driving pulley 94 rotates clockwise whereas the gears 96 and 98 rotate counter-clockwise. When the gears 96 and 98 rotate counter-clockwise, the bracket 99 carrying idler gear 91 moves toward the supply reel 8, and the idler gear 91 is meshed with supply reel gear 83 and rotates clockwise. If the idler gear 91 rotates clockwise, the supply reel gear 83 rotates counter-clockwise and the supply reel 88 also rotates counter-clockwise. Accordingly, the tape 85 is wound on the supply reel 88.
However, the conventional tape transport apparatus thus described requires a drum motor for driving the head drum and a capstan motor for transporting the tape. Accordingly, power consumption is increased considerably and the assembly of the VCR is complicated because of the use of plural motors. Also the number of parts is high resulting in an increased cost.